<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>扩展</title>
</head>

<body>
    <script>
        let score = +prompt('请输入你的成绩')
        switch (true) {
            case score < 60:
                alert('挨揍')
                break
            case score >= 60 && score < 70:
                alert('挨揍的边缘')
                break
            case score >= 70 && score < 80:
                alert('努力加油')
                break
            case score >= 80 && score < 90:
                alert('厉害，奖励棒棒糖')
                break
            default:
                alert('输入正确的成绩')
        }
    </script>
</body>

</html>